克拉玛依油田三区砾岩油藏水淹模式研究

水淹模式的系统总结是油藏水淹层快速识别和水淹级别准确判断的基础和关键。以克拉玛依油田三区克下组砾岩油藏为研究对象,分析水淹储层地球物理响应变化特征,依据区域测井资料研究水淹层岩石物理响应机理和测井响应特征,归纳出克下组砾岩油藏的5种水淹模式。利用电阻率径向幅度差确定水淹级别的模式有2种,结合2种水淹模式和试油结论制作砾岩油藏水淹级别定性评价的电性图版。砾岩油藏岩性复杂多变和非均质性严重,储层绝对电阻率对水淹级别不是很敏感,深中电阻率的差值可以有效判断水淹级别。基于储层沉积韵律和电性曲线判断水淹部位和水淹强度的模式有2种。沉积环境的变化导致储层纵向上物性和渗流性存在差异,注入水对储层流体的驱替就有选择性,水淹部位和水淹强度也会不同。依据自然电位基线偏移识别水淹部位的模式有1种,不同的泥岩基线偏移代表着储层不同部位的水淹情况。5种水淹模式的综合应用提高了三区砾岩油藏水淹层评价的精度。

On Water-flooded Pattern for Conglomerate Reservoir of the Third Block in Karamay Oilfield

The systematic summary of waterflooded pattern is the base and key to quickly identify water-flooded layers and accurately judge waterflooded levels.The Kexia Group conglomerate reservoir of the third district in Karamay oilfield is studied and variation features of geophysical responses after reservoir waterflooding are analyzed.Based on the above analysis the petrophysical response mechanisms and well logging response features of waterflooding layers are researched with the help of abundant well logging data,from which 5 water-flooded patterns in the above reservoir are generalized.Among which,① two patterns are determined by radial amplitude difference of the reservoir resistivity.A combination of the 2 patterns and testing conclusion helps us establish the resistivity plate of qualitative evaluation of water-flooded levels for the reservoir.Because the conglomerate reservoir lithology is complex and changeable with serious heterogeneity,reservoir absolute resistivity is not very sensitive to water-flooded levels but the difference of deep-middle resistivity may effectively judge the water-flooded levels.② two patterns are determined and used for judging water flooded location and intensity based on reservoir sedimentary rhythm and resistivity curves.The variable sedimentary environments lead to the longitudinal difference of reservoir physical property and seepage property,so injecting water is selectivity to displacing reservoir fluid and leads to the difference of water-flooded location and intensity.③ one pattern is used for identifying water-flooded location with the base line drift of natural potential.The different mudstone base line drifts represent different water-flooded locations.Comprehensive applications of the above 5 patterns improve evaluation accuracy of water-flooding layers for conglomerate reservoir of the third district.